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Q46 (IAS/2024) Science & Technology › New Materials, Energy & Environment-linked Tech › Biofuels and gasification Official Key

Consider the following materials : 1. Agricultural residues 2. Corn grain 3. Wastewater treatment sludge 4. Wood mill waste Which of the above can be used as feedstock for producing Sustainable Aviation Fuel ?

Result
Your answer: —  ·  Correct: C
Explanation

The correct answer is option C because all four materials—agricultural residues, corn grain, wastewater treatment sludge, and wood mill waste—can serve as feedstock for producing Sustainable Aviation Fuel (SAF).

Sustainable aviation fuel (SAF) is a synthetic fuel produced using non-petroleum feedstocks[1], and the carbon for synthetic fuels comes from biomass residues or seaweed, so-called short-cycle carbon[2]. Biomass is derived from numerous sources, including by-products from the timber industry, agricultural crops, residues from agriculture or forestry, and the organic component of municipal and industrial wastes[3].

Specifically, methanol (a potential SAF component) is produced from agricultural residue[4], confirming Statement 1. Corn grain, as an agricultural crop, falls under biomass feedstock. Anaerobic digestion can be used to treat industrial wastewater sludge, turning it into biogas[5], which can be converted to fuel, validating Statement 3. Pyrolysis of carbonaceous wastes like firewood and saw dust yields products that can be used as fuels[6], confirming Statement 4 regarding wood mill waste. Therefore, all four materials qualify as SAF feedstock.

Sources
  1. [2] https://hydrogen.unido.org/sites/default/files/2024-10/Green-energy-for-all-EN-lr-small.pdf
  2. [3] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 22: Renewable Energy > 22.6 BIOMASS > p. 292
  3. [4] Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 21: Sustainable Development and Climate Change > Methanol Economy > p. 604
  4. [5] https://www.unido.org/sites/default/files/unido-publications/2025-10/ndc-guidebook-vol2.pdf
  5. [6] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 5: Environmental Pollution > v) Pyrolysis > p. 86
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Q. Consider the following materials : 1. Agricultural residues 2. Corn grain 3. Wastewater treatment sludge 4. Wood mill waste Which of th…
At a glance
Origin: Books + Current Affairs Fairness: Moderate fairness Books / CA: 5/10 · 5/10
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This is a classic 'Possibility in Science' question. The keyword 'can be used' signals a test of technological potential, not just current commercial dominance. Since SAF technologies (like Gasification and Alcohol-to-Jet) are designed to be feedstock-agnostic for any carbon-based waste, the scope is naturally broad.

How this question is built

This question can be broken into the following sub-statements. Tap a statement sentence to jump into its detailed analysis.

Statement 1
Can agricultural residues be used as a feedstock for producing Sustainable Aviation Fuel (SAF)?
Origin: Direct from books Fairness: Straightforward Book-answerable
From standard books
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 23: India and Climate Change > Sources ofBio - Energy > p. 307
Presence: 5/5
“• Existing Sources • Leftover organic residue • Leftover farm organic residue • Leftover forest residue • Leftover organic urban residue • Algal residue • New Sources • Cultivation of short rotation energy crops • Social forestry”
Why this source?
  • Explicitly lists 'leftover farm organic residue' as an existing source of bio-energy.
  • Groups farm residues with other organic leftovers as usable feedstocks for energy production.
Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 22: Renewable Energy > 22.6 BIOMASS > p. 292
Presence: 4/5
“Biomass is a renewable energy resource derived from the carbonaceous waste of various human and natural activities. It is derived from numerous sources, including the by-products from the timber industry, agricultural crops, grassy and woody plants, residues from agriculture or forestry, oil-rich algae, and the organic component of municipal and industrial wastes. Biomass is a good substitute for the conventional fossil fuels for heating and energy generation purposes. Burning biomass releases about the same amount of carbon dioxide as burning fossil fuels, However, fossil fuels release carbon dioxide captured by photosynthesis over its formative years.”
Why this source?
  • Defines biomass to include residues from agriculture and forestry as inputs for renewable energy.
  • Frames biomass as a substitute for conventional fossil fuels, implying conversion of residues into fuels.
Indian Economy, Nitin Singhania .(ed 2nd 2021-22) > Chapter 21: Sustainable Development and Climate Change > Methanol Economy > p. 604
Presence: 4/5
“Methanol is a low-carbon, hydrogen carrier fuel. It is produced from high ash coal, agricultural residue, CO<sub>2</sub> from thermal power plants, etc. Methanol Economy program is initiated by NITI Aayog. It is aimed to reduce import of crude oil and reduce GHG emissions. It also intends to convert coal reserves and municipal solid waste into methanol and set up Methanol Production Plants. Blending of 15 per cent methanol in gasoline can result in at least 15 per cent reduction in import of gasoline/crude. It will reduce GHG emissions by 20 per cent in terms of particulate matter, NO<sub>x</sub> and SO<sub>x</sub>.”
Why this source?
  • States methanol can be produced from agricultural residue, showing residues are convertible into transport fuels.
  • Links residue-derived fuels to low-carbon fuel strategies and national fuel programs.
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